Copolycarbonate-polyesters, methods of manufacture, and uses thereof

ABSTRACT

A copolycarbonate-polyester, comprising units of formula  
                 
 
wherein at least 60 percent of the total number of R 1  groups are divalent aromatic organic radicals and the balance thereof are divalent aliphatic or alicyclic radicals; units of formula  
                 
 
wherein T is a C 7-20  divalent alkyl aromatic radical or a C 6-20  divalent aromatic radical, and D is a divalent C 6-20  aromatic radical; and units of the formula  
                 
 
wherein R 2  and R 3  are each independently a halogen or a C 1-6  alkyl group, R 4  is a methyl or phenyl group, each c is independently 0 to 4, and T is as described above.

BACKGROUND OF THE INVENTION

This disclosure relates to copolycarbonate-polyesters, and in particularto copolycarbonate-polyesters having improved thermal stability, methodsof manufacture, and uses thereof.

Polycarbonates derived from 2,2-bis(4-hydroxyphenyl)propane (“bisphenolA,” or “BPA”) are useful in the manufacture of articles and componentsfor a wide variety of applications, from automotive parts to electronicappliances. 3,3-Bis-(4-hydroxyphenyl)-2-phenyl-2,3-dihydroisoindol-1-one(“BHPD”), as a dihydric phenol reactant, has also been used in themanufacture of polycarbonates. BHPD, alone or in combination with BPA,yields high heat polymers, that is, polymers having a high glasstransition temperature (Tg). Use of BHPD in the manufacture ofpolyesters also leads to polymers having high Tg, but the process isvery sensitive, and the polyesters often have significantly lower flowthan polycarbonates with the same Tg. While current high heat polymersare suitable for their intended purposes, there nonetheless remains aneed in the art for additional high heat polymers that have improvedproperties, as well as methods for their manufacture.

SUMMARY OF THE INVENTION

In one embodiment, a copolycarbonate-polyester comprises units of theformula

wherein at least about 60 percent of the total number of R¹ groups aredivalent aromatic organic radicals and the balance thereof are divalentaliphatic, alicyclic, or aromatic radicals; units of the formula

wherein T is a divalent C₇₋₂₀ alkyl aromatic radical or a divalent C₆₋₂₀aromatic radical, and D is a C₆₋₂₀ divalent radical; and units of theformula

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl or phenyl group, each c is independently 0 to 4,and T is as described above.

In yet another embodiment, an article comprises the above-describedcopolycarbonate-polyester.

In still another embodiment, a method of manufacture of an articlecomprises casting, molding, extruding, or shaping the above-describedcopolycarbonate-polyester into an article.

In another embodiment, a method of manufacture comprises reacting adihydroxy-terminated polyester intermediate comprising units of formula

wherein T is a C₇₋₂₀ divalent alkyl aromatic radical or a C₆₋₂₀ divalentaromatic radical, and D is a divalent C₆₋₂₀ aromatic radical; and unitsof formula

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl, or phenyl group, each c is independently 0 to 4,with a carbonate source and a compound of the formula HO—R¹—OH in areaction mixture comprising water, a substantially water-immiscibleorganic solvent, and a base, to provide a copolycarbonate-polyester.

Another embodiment comprises a copolycarbonate-polyester manufactured bythe foregoing method, and an article comprising thecopolycarbonate-polyester.

DETAILED DESCRIPTION OF THE INVENTION

Copolycarbonate-polyesters comprising polycarbonate units and at leasttwo types of ester units are described herein. The polycarbonate unitsare derived from a dihydroxy aromatic compound. One type of ester unitis derived from the reaction of an aromatic dicarboxylic acid orderivative thereof with a high heat monomer such as BHPD, and anothertype of ester unit is derived from the reaction of an aromaticdicarboxylic acid or derivative thereof with an aromatic diol that isnot a high heat monomer. The copolymers can have excellent properties,including high Tg, high heat distortion temperature, good impactproperties, thermal stability, and/or resistance to yellowing.

As used herein, the term “polycarbonate units” means repeatingstructural carbonate units of formula (1)

in which at least about 60 percent of the total number of R¹ groups aredivalent aromatic organic radicals and the balance thereof are divalentaliphatic, alicyclic, or aromatic radicals. In one embodiment, each R¹is an aromatic organic radical, for example a radical of formula (2)-A¹-Y¹-A²-   (2)wherein each of A¹ and A² is a monocyclic divalent aryl radical and Y¹is a bridging radical having one or two atoms that separate A¹ from A².In an exemplary embodiment, one atom separates A¹ from A². Illustrativenon-limiting examples of radicals of this type are —O—, —S—, —S(O)—,—S(O₂)—, —C(O)—, methylene, cyclohexyl-methylene,2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene,neopentylidene, cyclohexylidene, cyclopentadecylidene,cyclododecylidene, and adamantylidene. The bridging radical Y¹ may be ahydrocarbon group or a saturated hydrocarbon group such as methylene,cyclohexylidene, or isopropylidene.

The carbonate units of formula (2) may be produced by the reaction ofdihydroxy compounds of the formula HO—R¹—OH, specifically a dihydroxycompound of formula (3)HO-A¹-Y¹-A²-OH   (3)wherein Y¹, A¹ and A² are as described above. Included are bisphenolcompounds of formula (4)

wherein R^(a) and R^(b) each represent a halogen atom or a monovalenthydrocarbon group and may be the same or different; p and q are eachindependently integers of 0 to 4; and X^(a) represents a group havingthe formula

wherein R^(c) and R^(d) each independently represent a hydrogen atom ora monovalent linear or cyclic hydrocarbon group and Re is a divalenthydrocarbon group.

Another type of suitable dihydroxy aromatic radical R¹ is derived froman aromatic dihydroxy compound of formula (5)

wherein each R^(f) is independently a halogen atom, a C₁₋₁₀ hydrocarbongroup, or a C₁₋₁₀ halogen substituted hydrocarbon group, and n is 0 to4. The halogen is usually bromine.

Bisphenols containing alkyl cyclohexane units may also be used, forexample those of formula (6)

wherein R^(g)—R^(j) are each independently hydrogen, C₁₋₁₂ alkyl, orhalogen; and R^(k)—R^(o) are each independently hydrogen or C₁₋₁₂ alkyl.Another example of a bisphenol containing a cycloalkane unit is thereaction product of two moles of a phenol with one mole of ahydrogenated isophorone.

Some illustrative, non-limiting examples of suitable dihydroxy compoundsinclude the following: 4,4′-dihydroxybiphenyl, 1,6-dihydroxynaphthalene,2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane,bis(4-hydroxyphenyl)diphenylmethane,bis(4-hydroxyphenyl)-1-naphthylmethane, 1,2-bis(4-hydroxyphenyl) ethane,1,1-bis(4-hydroxyphenyl)-1-phenylethane,2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane,bis(4-hydroxyphenyl)phenylmethane,2,2-bis(4-hydroxy-3-bromophenyl)propane, 1,1-bis(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane,1,1-bis(4-hydroxyphenyl)isobutene,1,1-bis(4-hydroxyphenyl)cyclododecane,trans-2,3-bis(4-hydroxyphenyl)-2-butene,2,2-bis(4-hydroxyphenyl)adamantine, (alpha,alpha′-bis(4-hydroxyphenyl)toluene, bis(4-hydroxyphenyl)acetonitrile,2,2-bis(3-methyl-4-hydroxyphenyl)propane,2,2-bis(3-ethyl-4-hydroxyphenyl)propane,2,2-bis(3-n-propyl-4-hydroxyphenyl)propane,2,2-bis(3-isopropyl-4-hydroxyphenyl)propane,2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane,2,2-bis(3-t-butyl-4-hydroxyphenyl)propane,2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,2,2-bis(3-allyl-4-hydroxyphenyl)propane,2,2-bis(3-methoxy-4-hydroxyphenyl)propane,2,2-bis(4-hydroxyphenyl)hexafluoropropane,1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene,1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene,1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene,4,4′-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone,1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycolbis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether,bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide,bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorine,2,7-dihydroxypyrene,6,6′-dihydroxy-3,3,3′,3′-tetramethylspiro(bis)indane (“spirobiindanebisphenol”), 3,3-bis(4-hydroxyphenyl)phthalide,2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene,2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine,3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and2,7-dihydroxycarbazole, resorcinol, substituted resorcinol compoundssuch as 4-bromoresorcinol, 5-methyl resorcinol, 5-ethyl resorcinol,5-propyl resorcinol, 5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenylresorcinol, 5-cumyl resorcinol, 2,4,5,6-tetrafluoro resorcinol,2,4,5,6-tetrabromo resorcinol, and the like, catechol, hydroquinone,substituted hydroquinones such as 2-methyl hydroquinone, 2-ethylhydroquinone, 2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butylhydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone,2,3,5,6-tetramethyl hydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone,2,3,5,6-tetrafluoro hydroquinone, and 2,3,5,6-tetrabromo, and the like,as well as combinations comprising at least one of the foregoingdihydroxy compounds.

Specific examples of the types of bisphenol compounds that may berepresented by formula 5 include 1,1-bis(4-hydroxyphenyl) methane,1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane,2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane,1,1-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)n-butane,2,2-bis(4-hydroxy-1-methylphenyl) propane,1,1-bis(4-hydroxy-t-butylphenyl)propane,3,3-bis(4-hydroxyphenyl)phthalimidine, and1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC). Combinationscomprising at least one of the foregoing dihydroxy compounds may also beused. In one specific embodiment, carbonate units of formula (3) derivedfrom bisphenol A are present, which each of A¹ and A² is p-phenylene andY¹ is isopropylidene in formula (4).

The copolycarbonate-polyesters further contain, in addition to recurringcarbonate chain units of formula (1), repeating units of formula (7)

wherein D is a divalent C₆₋₁₈ aromatic radical derived from an aromaticdiol, with the proviso that D is not derived from a high Tg monomer asdescribed below. In one embodiment, D is derived from an aromaticdihydroxy compound of formula (4) or (5) above. Mixtures of differenttypes of aromatic dihydroxy compounds can be used. The different typesof units can be present in the polymer chain as individual units, or asblocks comprising multiples of the same units.

T in formula (7) is a radical derived from a dicarboxylic acid, and canbe, for example, a divalent C₇₋₂₀ alkyl aromatic radical or a divalentC₆₋₂₀ aromatic radical. Examples of aromatic dicarboxylic acids that canbe used to prepare the polyester units include isophthalic orterephthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenylether, 4,4′-bisbenzoic acid, and mixtures comprising at least one of theforegoing acids. Acids containing fused rings can also be present, suchas in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids. Specificdicarboxylic acids are terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexane dicarboxylic acid, or mixtures thereof. Aspecific dicarboxylic acid comprises a mixture of isophthalic acid andterephthalic acid wherein the weight ratio of terephthalic acid toisophthalic acid is about 91:9 to about 2:98.

The copolycarbonate-polyesters further comprise ester units derived fromthe reaction of an aromatic dicarboxylic acid and a high Tg monomer offormula (8)

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl or phenyl group, and each c is independently 0 to4. In a specific embodiment, each c is 0. In another embodiment, R⁴ is aphenyl group. In another specific embodiment, the high Tg monomer isBHPD, which has the following formula:

The ester units derived from the reaction of an aromatic dicarboxylicacid and a high Tg monomer of formula (8) are of formula (9)

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl or phenyl group, each c is independently 0 to 4,and T is as described above. The different types of units represented byformulas (7) and (9) can be present in the polymer chain as individualunits, or as blocks comprising multiples of the same units.

In one specific embodiment, D is a C₆₋₁₂ arylene radical and T isp-phenylene, m-phenylene, naphthalenyl, or a mixture thereof. In anotherspecific embodiment, one or both of the polyester units of formula (7)and (9) are derived from the reaction of a combination of isophthalicand terephthalic diacids (or derivatives thereof) with resorcinol. Instill another specific embodiment, the polyester unit of formula (7) isderived from the reaction of a combination of isophthalic acid andterephthalic acid with bisphenol-A. In any one or more of the foregoingspecific embodiments, the polycarbonate units are derived from bisphenolA.

The copolycarbonate-polyesters can be manufactured by processes such asinterfacial polymerization. Although the reaction conditions forinterfacial polymerization can vary, an exemplary process generallyinvolves dissolving or dispersing a dihydroxy compound in aqueouscaustic soda or potash, adding the resulting mixture to a suitablewater-immiscible solvent medium, and contacting the reactants with anaromatic dicarboxylic acid or derivative thereof in the presence of asuitable catalyst such as triethylamine or a phase transfer catalyst,under controlled pH conditions, e.g., about 8 to about 10, to produce areactive polyester intermediate. The most commonly used water immisciblesolvents include methylene chloride, 1,2-dichloroethane, chlorobenzene,toluene, and the like.

Among the phase transfer catalysts that can be used are catalysts of theformula (R¹⁰)₄Q⁺X, wherein each R¹⁰ is the same or different, and is aC₁₋₁₀ alkyl group; Q is a nitrogen or phosphorus atom; and X is ahalogen atom, a hydroxide, a C₁₋₈ alkoxy group or C₆₋₁₈ aryloxy group.Suitable phase transfer catalysts include, for example, [CH₃(CH₂)₃]₄NX,[CH₃(CH₂)₃]₄PX, [CH₃(CH₂)₅]₄NX, [CH₃(CH₂)₆]₄NX, [CH₃(CH₂)₄]₄NX,CH₃[CH₃(CH₂)₃]₃NX, and CH₃[CH₃(CH₂)₂]₃NX, wherein X is Cl⁻, Br⁻, a C₁₋₈alkoxy group or a C₆₋₁₈ aryloxy group. In a specific embodiment X is ahalogen such as chloride or a hydroxyl group. An effective amount of aphase transfer catalyst is typically about 0.1 to about 10 wt. %,specifically about 0.5 to about 2 wt. % based on the weight of bisphenolin the reaction mixture.

Rather than utilizing the dicarboxylic acid per se, it is possible, andsometimes even preferred, to employ the reactive derivatives of theacid, such as the corresponding acid halides, in particular the aciddichlorides and the acid dibromides. Thus, for example instead of usingisophthalic acid, terephthalic acid, or mixtures thereof, it is possibleto employ isophthaloyl dichloride, terephthaloyl dichloride, andmixtures thereof.

The reactive polyester intermediate can be dihydroxy-terminated or acidhalide-terminated, depending on reaction conditions. For example,hydroxy-terminated polyester oligomers can be formed by using an excessof the dihydroxy compounds. Acid halide-terminated polyester oligomerscan be formed by using an excess of acid chloride. The reactivepolyester intermediate may or may not be isolated. For ease ofmanufacture, the reaction mixture containing the reactive polyesterintermediate is not isolated, but is directly contacted with a carbonateprecursor, for example a carbonyl halide such as carbonyl bromide orcarbonyl chloride, or a haloformate such as a bishaloformate of adihydric phenol (e.g., the bischloroformates of bisphenol A,hydroquinone, or the like). Combinations comprising at least one of theforegoing types of carbonate precursors may also be used.

The contacting is carried out in the presence of a compound having theformula HO—R¹—OH, to provide the carbonate units of formula (1). In oneembodiment, the same dihydroxy compound is used to provide both themoiety D in formula (8) and the moiety R¹ in formula (1). Alternatively,a different dihydroxy compound than that used to provide the moiety D informula (8) is used.

The molar ratio of carbonate units to ester units in the copolymers canvary broadly depending on the identity of the carbonate units and esterunits, and the desired properties of the copolymer. The ratio ofcarbonate units to ester units can be adjusted from 1:99 to 99:1,specifically 10:90 to 90:10, more specifically, 20:80 to 80:20, 30:70 to70:30, 40:60 to 60:40, or 50:50 to any one of the foregoing end points,by adjusting the relative ratio of starting material and reactionconditions.

The molar ratio ester units of formula (7) (those derived from anaromatic diol, i.e., HO-D-OH) to ester units of formula (9) (thosederived from a high Tg monomer) in the copolymer can be adjusted byvarying the ratio of the diol to BHPD in the starting mixture, as wellas reaction conditions. The molar ratio of ester units of formula (7) toester units of formula (9) is adjusted to 0.1:99.9 to 99.9:0.1,depending on the T groups, the R¹ groups, and the desired end propertiesof the copolymer. In various embodiments, the molar ratio of ester unitsof formula (7) to ester units of formula (9) is 1:99 to 99:1, 10:90 to90:10,20:80 to 80:20, 30:70 to 70:30, 40:60 to 60:40 or 50:50 to any oneof the foregoing endpoints.

Another feature of the copolymers that is subject to variation bycontrol of starting materials and reaction conditions is the relativelength of the polyester blocks and polycarbonate blocks. For example, itmay be desirable to produce copolymers having relatively shorterpolyester blocks and relatively longer polycarbonate blocks; copolymershaving polyester blocks and polycarbonate blocks of approximately equallength; or copolymers having relatively longer polyester blocks andrelatively shorter polycarbonate blocks. It may also be desirable tohave a narrower or broader distribution of block lengths for either thepolyester blocks, the polycarbonate blocks, or both. For example,copolymers having a narrow distribution of shorter polyester blocks witha narrower or broader distribution of longer polycarbonate blocks mayresult in more transparent polymers.

Those of skill in the art will readily recognize that during theinterfacial reaction of mixtures comprising the high Tg monomer, acertain amount of the high Tg monomer can become incorporated into thecopolymer as carbonate units. The relative degree of such incorporationcan be adjusted by varying the type of monomers used in the othercopolymer units and the reaction conditions. In one embodiment, thenumber of carbonate units derived from BHPD in the copolymers is lessthan 50% of the total number of carbonate units, specifically less than40%, more specifically less than 30%, still more specifically less than20%, and even more specifically less than 10%, down to 1% of the totalnumber of carbonate units.

The copolycarbonate-polyesters have a number of desirable properties,including high Tg, high heat distortion temperature, good impactproperties, thermal stability, absence of color, and/or resistance toyellowing.

The amount and type of other polymers and/or additives used with thecopolycarbonate-polyesters are selected so as to provide the desiredproperties to the copolycarbonate-polyesters without substantiallyadversely impacting other properties needed for a given application.Such selections may be made without undue experimentation by one ofordinary skill in the art, based on the desired properties of thecomposition and the known properties of the additives. For example, useof certain polymers and/or additives can be limited by the processingconditions used for the copolycarbonate-polyesters. In one embodimentdescribed below, films comprising the copolycarbonate-polyesters areformed by solution casting. Other polymers and/or additives (forexample, impact modifiers, UV stabilizers, and the like), willpreferably also be soluble in the solution used to cast the film. Theamount and type of other polymers and/or additives used with thecopolycarbonate-polyesters may also be limited by the intendedapplication. For example, where a transparent film is desired, it maynot be possible to use certain impact modifiers, fillers, colorants, oranti-drip agents.

The copolycarbonate-polyesters described herein can be used incombination with other polymers, including other homopolycarbonates,polycarbonate copolymers comprising different R¹ groups, and/orcopolymers comprising polycarbonate units and other polymer units suchas ester units or diorganosiloxane units. As used herein, a“combination” is inclusive of blends, mixtures, alloys, and the like.The copolycarbonates may also be used in combination with otherpolymers, for example polyesters such as polyarylates, polyacetals,polystyrenes, polyamides, polyamideimides, polyimides, polyetherimides,polysulfones such as polyarylsulfones and polyethersulfones,polysulfonates, polysulfonamides polysulfides such as polyphenylenesulfides, polythioesters, polytetrafluoroethylenes, polyetherketones,polyether etherketones, polyether ketone ketones, polyvinyl ethers,polyvinyl thioethers, polyvinyl, polyvinyl ketones, polyvinyl halidesalcohols such as polyvinyl chlorides, polyvinyl nitriles, polyvinylesters, or a combination comprising at least one of the foregoingpolymers.

The copolycarbonate-polyesters may further be combined with an impactmodifier composition, to increase impact resistance. These impactmodifiers include elastomer-modified graft copolymers comprising (i) anelastomeric (i.e., rubbery) polymer substrate having a Tg less thanabout 10° C., more specifically less than about −10° C., or morespecifically about −40° to −80° C., and (ii) a rigid polymericsuperstrate grafted to the elastomeric polymer substrate. As is known,elastomer-modified graft copolymers may be prepared by first providingthe elastomeric polymer, then polymerizing the constituent monomer(s) ofthe rigid phase in the presence of the elastomer to obtain the graftcopolymer. The grafts may be attached as graft branches or as shells toan elastomer core. The shell may merely physically encapsulate the core,or the shell may be partially or essentially completely grafted to thecore.

Suitable materials for use as the elastomer phase include, for example,conjugated diene rubbers; copolymers of a conjugated diene with lessthan about 50 wt. % of a copolymerizable monomer; olefin rubbers such asethylene propylene copolymers (EPR) or ethylene-propylene-diene monomerrubbers (EPDM); ethylene-vinyl acetate rubbers; silicone rubbers;elastomeric C₁₋₈ alkyl (meth)acrylates; elastomeric copolymers of C₁₋₈alkyl (meth)acrylates with butadiene and/or styrene; or combinationscomprising at least one of the foregoing elastomers.

Suitable conjugated diene monomers for preparing the elastomer phase areof formula (10)

wherein each X^(b) is independently hydrogen, C₁-C₅ alkyl, or the like.Examples of conjugated diene monomers that may be used are butadiene,isoprene, 1,3-heptadiene, methyl-1,3-pentadiene,2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-pentadiene; 1,3- and2,4-hexadienes, and the like, as well as mixtures comprising at leastone of the foregoing conjugated diene monomers. Specific conjugateddiene homopolymers include polybutadiene and polyisoprene.

Copolymers of a conjugated diene rubber may also be used, for examplethose produced by aqueous radical emulsion polymerization of aconjugated diene and one or more monomers copolymerizable therewith.Monomers that are suitable for copolymerization with the conjugateddiene include monovinylaromatic monomers containing condensed aromaticring structures, such as vinyl naphthalene, vinyl anthracene and thelike, or monomers of formula (11)

wherein each X^(c) is independently hydrogen, C₁-C₁₂ alkyl, C₃-C₁₂cycloalkyl, C₆-C₁₂ aryl, C₇-C₁₂ aralkyl, C₇-C₁₂ alkaryl, C₁-C₁₂ alkoxy,C₃-C₁₂ cycloalkoxy, C₆-C₁₂ aryloxy, chloro, bromo, or hydroxy, and R ishydrogen, C₁-C₅ alkyl, bromo, or chloro. Examples of suitablemonovinylaromatic monomers that may be used include styrene,3-methylstyrene, 3,5-diethylstyrene, 4-n-propylstyrene,alpha-methylstyrene, alpha-methyl vinyltoluene, alpha-chlorostyrene,alpha-bromostyrene, dichlorostyrene, dibromostyrene,tetra-chlorostyrene, and the like, and combinations comprising at leastone of the foregoing compounds. Styrene and/or alpha-methylstyrene maybe used as monomers copolymerizable with the conjugated diene monomer.

Other monomers that may be copolymerized with the conjugated diene aremonovinylic monomers such as itaconic acid, acrylamide, N-substitutedacrylamide or methacrylamide, maleic anhydride, maleimide, N-alkyl-,aryl-, or haloaryl-substituted maleimide, glycidylmeth)acrylates, andmonomers of the generic formula (10)

wherein R is hydrogen, C₁-C₅ alkyl, bromo, or chloro, and X^(c) iscyano, C₁-C₁₂ alkoxycarbonyl, C₁-C₁₂ aryloxycarbonyl, hydroxy carbonyl,or the like. Examples of monomers of formula (12) include acrylonitrile,ethacrylonitrile, methacrylonitrile, alpha-chloroacrylonitrile,beta-chloroacrylonitrile, alpha-bromoacrylonitrile, acrylic acid,methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate,t-butyl(meth)acrylate, n-propyl(meth)acrylate, isopropyl(meth)acrylate,2-ethylhexyl(meth)acrylate, and the like, and combinations comprising atleast one of the foregoing monomers. Monomers such as n-butyl acrylate,ethyl acrylate, and 2-ethylhexyl acrylate are commonly used as monomerscopolymerizable with the conjugated diene monomer. Mixtures of theforegoing monovinyl monomers and monovinylaromatic monomers may also beused.

Suitable (meth)acrylate monomers suitable for use as the elastomericphase may be cross-linked, particulate emulsion homopolymers orcopolymers of C₁₋₈ alkyl(meth)acrylates, in particular C₄₋₆ alkylacrylates, for example n-butyl acrylate, t-butyl acrylate, n-propylacrylate, isopropyl acrylate, 2-ethylhexyl acrylate, and th like, andcombinations comprising at least one of the foregoing monomers. The C₁₋₈alkyl(meth)acrylate monomers may optionally be polymerized in admixturewith up to 15 wt. % of comonomers of formulas (8), (9), or (10).Exemplary comonomers include but are not limited to butadiene, isoprene,styrene, methyl methacrylate, phenyl methacrylate, penethylmethacrylate,N-cyclohexylacrylamide, vinyl methyl ether or acrylonitrile, andmixtures comprising at least one of the foregoing comonomers.Optionally, up to 5 wt. % a polyfunctional crosslinking comonomer may bepresent, for example divinylbenzene, alkylenediol di(meth)acrylates suchas glycol bisacrylate, alkylenetriol tri(meth)acrylates, polyesterdi(meth)acrylates, bisacrylamides, triallyl cyanurate, triallylisocyanurate, allyl(meth)acrylate, diallyl maleate, diallyl fumarate,diallyl adipate, triallyl esters of citric acid, triallyl esters ofphosphoric acid, and the like, as well as combinations comprising atleast one of the foregoing crosslinking agents.

The elastomer phase may be polymerized by mass, emulsion, suspension,solution or combined processes such as bulk-suspension, emulsion-bulk,bulk-solution or other techniques, using continuous, semibatch, or batchprocesses. The particle size of the elastomer substrate is not critical.For example, an average particle size of about 0.001 to about 25micrometers, specifically about 0.01 to about 15 micrometers, or evenmore specifically about 0.1 to about 8 micrometers may be used foremulsion based polymerized rubber lattices. A particle size of about 0.5to about 10 micrometers, specifically about 0.6 to about 1.5 micrometersmay be used for bulk polymerized rubber substrates. Particle size may bemeasured by simple light transmission methods or capillary hydrodynamicchromatography (CHDF). The elastomer phase may be a particulate,moderately cross-linked conjugated butadiene or C₄₋₆ alkyl acrylaterubber, and preferably has a gel content greater than 70%. Also suitableare mixtures of butadiene with styrene and/or C₄₋₆ alkyl acrylaterubbers.

The elastomeric phase may provide about 5 to about 95 wt. % of the totalgraft copolymer, more specifically about 20 to about 90 wt. %, and evenmore specifically about 40 to about 85 wt. % of the elastomer-modifiedgraft copolymer, the remainder being the rigid graft phase.

The rigid phase of the elastomer-modified graft copolymer may be formedby graft polymerization of a mixture comprising a monovinylaromaticmonomer and optionally one or more comonomers in the presence of one ormore elastomeric polymer substrates. The above-describedmonovinylaromatic monomers of formula (11) may be used in the rigidgraft phase, including styrene, alpha-methyl styrene, halostyrenes suchas dibromostyrene, vinyltoluene, vinylxylene, butylstyrene,para-hydroxystyrene, methoxystyrene, or the like, or combinationscomprising at least one of the foregoing monovinylaromatic monomers.Suitable comonomers include, for example, the above-describedmonovinylic monomers and/or monomers of the general formula (12). In oneembodiment, R is hydrogen or C₁-C₂ alkyl, and X^(c) is cyano or C₁-C₁₂alkoxycarbonyl. Specific examples of suitable comonomers for use in therigid phase include acrylonitrile, ethacrylonitrile, methacrylonitrile,methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate,isopropyl(meth)acrylate, and the like, and combinations comprising atleast one of the foregoing comonomers.

The relative ratio of monovinylaromatic monomer and comonomer in therigid graft phase may vary widely depending on the type of elastomersubstrate, type of monovinylaromatic monomer(s), type of comonomer(s),and the desired properties of the impact modifier. The rigid phase maygenerally comprise up to 100 wt. % of monovinyl aromatic monomer,specifically about 30 to about 100 wt. %, more specifically about 50 toabout 90 wt. % monovinylaromatic monomer, with the balance beingcomonomer(s).

Depending on the amount of elastomer-modified polymer present, aseparate matrix or continuous phase of ungrafted rigid polymer orcopolymer may be simultaneously obtained along with theelastomer-modified graft copolymer. Typically, such impact modifierscomprise about 40 to about 95 wt. % elastomer-modified graft copolymerand about 5 to about 65 wt. % graft (co)polymer, based on the totalweight of the impact modifier. In another embodiment, such impactmodifiers comprise about 50 to about 85 wt. %, more specifically about75 to about 85 wt. % rubber-modified graft copolymer, together withabout 15 to about 50 wt. %, more specifically about 15 to about 25 wt. %graft (co)polymer, based on the total weight of the impact modifier.

Another specific type of elastomer-modified impact modifier comprisesstructural units derived from at least one silicone rubber monomer, abranched acrylate rubber monomer having the formulaH₂C═C(R^(d))C(O)OCH₂CH₂R^(e), wherein R^(d) is hydrogen or a C₁-C₈linear or branched alkyl group and Re is a branched C₃-C₁₆ alkyl group;a first graft link monomer; a polymerizable alkenyl-containing organicmaterial; and a second graft link monomer. The silicone rubber monomermay comprise, for example, a cyclic siloxane, tetraalkoxysilane,trialkoxysilane, (acryloxy)alkoxysilane, (mercaptoalkyl)alkoxysilane,vinylalkoxysilane, or allylalkoxysilane, alone or in combination, e.g.,decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane,trimethyltriphenylcyclotrisiloxane,tetramethyltetraphenylcyclotetrasiloxane,tetramethyltetravinylcyclotetrasiloxane, octaphenylcyclotetrasiloxane,octamethylcyclotetrasiloxane and/or tetraethoxysilane.

Exemplary branched acrylate rubber monomers include iso-octyl acrylate,6-methyloctyl acrylate, 7-methyloctyl acrylate, 6-methylheptyl acrylate,and the like, alone or in combination. The polymerizablealkenyl-containing organic material may be, for example, a monomer offormula (11) or (12), e.g., styrene, alpha-methylstyrene, acrylonitrile,methacrylonitrile, or an unbranched (meth)acrylate such as methylmethacrylate, 2-ethylhexyl methacrylate, methyl acrylate, ethylacrylate, n-propyl acrylate, or the like, alone or in combination.

The at least one first graft link monomer may be an(acryloxy)alkoxysilane, a (mercaptoalkyl)alkoxysilane, avinylalkoxysilane, or an allylalkoxysilane, alone or in combination,e.g., (gamma-methacryloxypropyl)(dimethoxy)methylsilane and/or(3-mercaptopropyl)trimethoxysilane. The at least one second graft linkmonomer is a polyethylenically unsaturated compound having at least oneallyl group, such as allyl methacrylate, triallyl cyanurate, or triallylisocyanurate, alone or in combination.

The silicone-acrylate impact modifier compositions can be prepared byemulsion polymerization, wherein, for example at least one siliconerubber monomer is reacted with at least one first graft link monomer ata temperature from about 30° C. to about 110° C. to form a siliconerubber latex, in the presence of a surfactant such asdodecylbenzenesulfonic acid. Alternatively, a cyclic siloxane such ascyclooctamethyltetrasiloxane and a tetraethoxyorthosilicate may bereacted with a first graft link monomer such as(gamma-methacryloxypropyl)methyldimethoxysilane, to afford siliconerubber having an average particle size from about 100 nanometers toabout 2 microns. At least one branched acrylate rubber monomer is thenpolymerized with the silicone rubber particles, optionally in presenceof a cross linking monomer, such as allylmethacrylate in the presence ofa free radical generating polymerization catalyst such as benzoylperoxide. This latex is then reacted with a polymerizablealkenyl-containing organic material and a second graft link monomer. Thelatex particles of the graft silicone-acrylate rubber hybrid may beseparated from the aqueous phase through coagulation (by treatment witha coagulant) and dried to a fine powder to produce the silicone-acrylaterubber impact modifier composition. This method can be generally usedfor producing the silicone-acrylate impact modifier having a particlesize from about 100 nanometers to about two micrometers.

Processes known for the formation of the foregoing elastomer-modifiedgraft copolymers include mass, emulsion, suspension, and solutionprocesses, or combined processes such as bulk-suspension, emulsion-bulk,bulk-solution or other techniques, using continuous, semibatch, or batchprocesses.

In one embodiment the foregoing types of impact modifiers are preparedby an emulsion polymerization process that is free of basic materialssuch as alkali metal salts of C₆₋₃₀ fatty acids, for example sodiumstearate, lithium stearate, sodium oleate, potassium oleate, and thelike, alkali metal carbonates, amines such as dodecyl dimethyl amine,dodecyl amine, and the like, and ammonium salts of amines. Suchmaterials are commonly used as surfactants in emulsion polymerization,and may catalyze transesterification and/or degradation ofpolycarbonates. Instead, ionic sulfate, sulfonate or phosphatesurfactants may be used in preparing the impact modifiers, particularlythe elastomeric substrate portion of the impact modifiers. Suitablesurfactants include, for example, C₁₋₂₂ alkyl or C₇₋₂₅ alkylarylsulfonates, C₁₋₂₂ alkyl or C₇₋₂₅ alkylaryl sulfates, C₁₋₂₂ alkyl orC₇₋₂₅ alkylaryl phosphates, substituted silicates, and mixtures thereof.A specific surfactant is a C₆₋₁₆, specifically a C₈₋₁₂ alkyl sulfonate.This emulsion polymerization process is described and disclosed invarious patents and literature of such companies as Rohm & Haas andGeneral Electric Company. In the practice, any of the above-describedimpact modifiers may be used providing it is free of the alkali metalsalts of fatty acids, alkali metal carbonates and other basic materials.

A specific impact modifier of this type is an MBS impact modifierwherein the butadiene substrate is prepared using above-describedsulfonates, sulfates, or phosphates as surfactants. It is also preferredthat the impact modifier have a pH of about 3 to about 8, specificallyabout 4 to about 7.

Various additives ordinarily incorporated into the copolymer resincompositions, with the proviso that the additives are preferablyselected so as to not significantly adversely affect the desiredproperties of the copolycarbonate-polyesters. Mixtures of additives maybe used. Such additives may be mixed at a suitable time during themixing of the components for forming the composition.

Suitable fillers or reinforcing agents include, for example, silicatesand silica powders such as aluminum silicate (mullite), syntheticcalcium silicate, zirconium silicate, fused silica, crystalline silicagraphite, natural silica sand, or the like; boron powders such asboron-nitride powder, boron-silicate powders, or the like; oxides suchas TiO₂, aluminum oxide, magnesium oxide, or the like; calcium sulfate(as its anhydride, dihydrate or trihydrate); calcium carbonates such aschalk, limestone, marble, synthetic precipitated calcium carbonates, orthe like; talc, including fibrous, modular, needle shaped, lamellartalc, or the like; wollastonite; surface-treated wollastonite; glassspheres such as hollow and solid glass spheres, silicate spheres,cenospheres, aluminosilicate (armospheres), or the like; kaolin,including hard kaolin, soft kaolin, calcined kaolin, kaolin comprisingvarious coatings known in the art to facilitate compatibility with thepolymeric matrix resin, or the like; single crystal fibers or “whiskers”such as silicon carbide, alumina, boron carbide, iron, nickel, copper,or the like; fibers (including continuous and chopped fibers) such asasbestos, carbon fibers, glass fibers, such as E, A, C, ECR, R, S, D, orNE glasses, or the like; sulfides such as molybdenum sulfide, zincsulfide or the like; barium compounds such as barium titanate, bariumferrite, barium sulfate, heavy spar, or the like; metals and metaloxides such as particulate or fibrous aluminum, bronze, zinc, copper andnickel or the like; flaked fillers such as glass flakes, flaked siliconcarbide, aluminum diboride, aluminum flakes, steel flakes or the like;fibrous fillers, for example short inorganic fibers such as thosederived from blends comprising at least one of aluminum silicates,aluminum oxides, magnesium oxides, and calcium sulfate hemihydrate orthe like; natural fillers and reinforcements, such as wood flourobtained by pulverizing wood, fibrous products such as cellulose,cotton, sisal, jute, starch, cork flour, lignin, ground nut shells,corn, rice grain husks or the like; organic fillers such aspolytetrafluoroethylene; reinforcing organic fibrous fillers formed fromorganic polymers capable of forming fibers such as poly(ether ketone),polyimide, polybenzoxazole, poly(phenylene sulfide), polyesters,polyethylene, aromatic polyamides, aromatic polyimides, polyetherimides,polytetrafluoroethylene, acrylic resins, poly(vinyl alcohol) or thelike; as well as additional fillers and reinforcing agents such as mica,clay, feldspar, flue dust, fillite, quartz, quartzite, perlite, tripoli,diatomaceous earth, carbon black, or the like, or combinationscomprising at least one of the foregoing fillers or reinforcing agents.

The fillers and reinforcing agents may be coated with a layer ofmetallic material to facilitate conductivity, or surface treated withsilanes to improve adhesion and dispersion with the polymeric matrixresin. In addition, the reinforcing fillers may be provided in the formof monofilament or multifilament fibers and may be used either alone orin combination with other types of fiber, through, for example,co-weaving or core/sheath, side-by-side, orange-type or matrix andfibril constructions, or by other methods known to one skilled in theart of fiber manufacture. Suitable cowoven structures include, forexample, glass fiber-carbon fiber, carbon fiber-aromatic polyimide(aramid) fiber, and aromatic polyimide fiberglass fiber or the like.Fibrous fillers may be supplied in the form of, for example, rovings,woven fibrous reinforcements, such as 0-90 degree fabrics or the like;non-woven fibrous reinforcements such as continuous strand mat, choppedstrand mat, tissues, papers and felts or the like; or three-dimensionalreinforcements such as braids. Fillers are generally used in amounts ofabout 1 to about 500 parts by weight, based on 100 parts by weight ofthe copolycarbonate-polyester resin.

Suitable antioxidant additives include, for example, organophosphitessuch as tris(nonyl phenyl)phosphite,tris(2,4-di-t-butylphenyl)phosphite,bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, distearylpentaerythritol diphosphite or the like; alkylated monophenols orpolyphenols; alkylated reaction products of polyphenols with dienes,such astetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane,or the like; butylated reaction products of para-cresol ordicyclopentadiene; alkylated hydroquinones; hydroxylated thiodiphenylethers; alkylidene-bisphenols; benzyl compounds; esters ofbeta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid with monohydricor polyhydric alcohols; esters ofbeta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid withmonohydric or polyhydric alcohols; esters of thioalkyl or thioarylcompounds such as distearylthiopropionate, dilaurylthiopropionate,ditridecylthiodipropionate,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionateor the like; amides ofbeta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid or the like, orcombinations comprising at least one of the foregoing antioxidants.Antioxidants are generally used in amounts of about 1 to about 10 partsby weight, based on 100 parts by weight of the copolycarbonate-polyesterresin.

Suitable heat stabilizer additives include, for example,organophosphites such as triphenyl phosphite,tris-(2,6-dimethylphenyl)phosphite, tris-(mixed mono-anddi-nonylphenyl)phosphite or the like; phosphonates such asdimethylbenzene phosphonate or the like, aromatic phosphines such astriphenylphosphine, or combinations comprising at least one of theforegoing heat stabilizers. Heat stabilizers are generally used inamounts of about 1 to about 10 parts by weight, based on 100 parts byweight of the copolycarbonate-polyester resin.

Light stabilizers and/or ultraviolet light (UV) absorbing additives mayalso be used. Suitable light stabilizer additives include, for example,benzotriazoles such as 2-(2-hydroxy-5-methylphenyl)benzotriazole,2-(2-hydroxy-5-tert-octylphenyl)-benzotriazole and 2-hydroxy-4-n-octoxybenzophenone, or the like, or combinations comprising at least one ofthe foregoing light stabilizers. Light stabilizers are generally used inamounts of about 1 to about 10 parts by weight, based on 100 parts byweight of the copolycarbonate-polyester resin.

Suitable UV absorbing additives include for example,hydroxybenzophenones; hydroxybenzotriazoles; hydroxybenzotriazines;cyanoacrylates; oxanilides; benzoxazinones;2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (CYASORB™5411); 2-hydroxy-4-n-octyloxybenzophenone (CYASORB™ 531);2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)-phenol(CYASORB™ 1164); 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one)(CYASORB™ UV-3638);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane (UVINUL™ 3030);2,2′-(1,4-phenylene) bis(4H-3,1-benzoxazin-4-one);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane;nano-size inorganic materials such as titanium oxide, cerium oxide, andzinc oxide, all with particle size less than about 100 nanometers; orthe like, or combinations comprising at least one of the foregoing UVabsorbers. UV absorbers are generally used in amounts of about 1 toabout 10 parts by weight, based on 100 parts by weight of thecopolycarbonate-polyester resin.

Plasticizers, lubricants, and/or mold release agents additives may alsobe used. There is considerable overlap among these types of materials,which include, for example, phthalic acid esters such asdioctyl-4,5-epoxy-hexahydrophthalate;tris-(octoxycarbonylethyl)isocyanurate; tristearin; di- orpolyfunctional aromatic phosphates such as resorcinol tetraphenyldiphosphate (RDP), the bis(diphenyl) phosphate of hydroquinone and thebis(diphenyl) phosphate of bisphenol-A; poly-alpha-olefins; epoxidizedsoybean oil; silicones, including silicone oils; esters, for example,fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate;stearyl stearate, pentaerythritol tetrastearate, and the like; mixturesof methyl stearate and hydrophilic and hydrophobic nonionic surfactantscomprising polyethylene glycol polymers, polypropylene glycol polymers,and copolymers thereof, e.g., methyl stearate andpolyethylene-polypropylene glycol copolymers in a suitable solvent;waxes such as beeswax, montan wax, paraffin wax or the like. Suchmaterials are generally used in amounts of about 1 to about 25 parts byweight, based on 100 parts by weight of the copolycarbonate-polyesterresin.

The term “antistatic agent” refers to monomeric, oligomeric, orpolymeric materials that can be processed into polymer resins and/orsprayed onto materials or articles to improve conductive properties andoverall physical performance. Examples of monomeric antistatic agentsinclude glycerol monostearate, glycerol distearate, glyceroltristearate, ethoxylated amines, primary, secondary and tertiary amines,ethoxylated alcohols, alkyl sulfates, alkylarylsulfates,alkylphosphates, alkylaminesulfates, alkyl sulfonate salts such assodium stearyl sulfonate, sodium dodecylbenzenesulfonate or the like,quaternary ammonium salts, quaternary ammonium resins, imidazolinederivatives, sorbitan esters, ethanolamides, betaines, or the like, orcombinations comprising at least one of the foregoing monomericantistatic agents.

Exemplary polymeric antistatic agents include certain polyesteramidespolyether-polyamide (polyetheramide) block copolymers,polyetheresteramide block copolymers, polyetheresters, or polyurethanes,each containing polyalkylene glycol moieties polyalkylene oxide unitssuch as polyethylene glycol, polypropylene glycol, polytetramethyleneglycol, and the like. Such polymeric antistatic agents are commerciallyavailable, for example Pelestat™ 6321 (Sanyo) or Pebax™ MH1657(Atofina), Irgastat™ P18 and P22 (Ciba-Geigy). Other polymeric materialsthat may be used as antistatic agents are inherently conducting polymerssuch as polyaniline (commercially available as PANIPOL™EB from Panipol),polypyrrole and polythiophene (commercially available from Bayer), whichretain some of their intrinsic conductivity after melt processing atelevated temperatures. In one embodiment, carbon fibers, carbonnanofibers, carbon nanotubes, carbon black, or any combination of theforegoing may be used in a polymeric resin containing chemicalantistatic agents to render the composition electrostaticallydissipative. Antistatic agents are generally used in amounts of about 1to about 25 parts by weight, based on 100 parts by weight of thecopolycarbonate-polyester resin.

Colorants such as pigment and/or dye additives may also be present.Suitable pigments include for example, inorganic pigments such as metaloxides and mixed metal oxides such as zinc oxide, titanium dioxides,iron oxides or the like; sulfides such as zinc sulfides, or the like;aluminates; sodium sulfo-silicates sulfates, chromates, or the like;carbon blacks; zinc ferrites; ultramarine blue; Pigment Brown 24;Pigment Red 101; Pigment Yellow 119; organic pigments such as azos,di-azos, quinacridones, perylenes, naphthalene tetracarboxylic acids,flavanthrones, isoindolinones, tetrachloroisoindolinones,anthraquinones, anthanthrones, dioxazines, phthalocyanines, and azolakes; Pigment Blue 60, Pigment Red 122, Pigment Red 149, Pigment Red177, Pigment Red 179, Pigment Red 202, Pigment Violet 29, Pigment Blue15, Pigment Green 7, Pigment Yellow 147 and Pigment Yellow 150, orcombinations comprising at least one of the foregoing pigments. Pigmentsare generally used in amounts of about 1 to about 25 parts by weight,based on 100 parts by weight of the copolycarbonate-polyester resin.

Suitable dyes are generally organic materials and include, for example,coumarin dyes such as coumarin 460 (blue), coumarin 6 (green), nile redor the like; lanthanide complexes; hydrocarbon and substitutedhydrocarbon dyes; polycyclic aromatic hydrocarbon dyes; scintillationdyes such as oxazole or oxadiazole dyes; aryl- or heteroaryl-substitutedpoly (C₂₋₈) olefin dyes; carbocyanine dyes; indanthrone dyes;phthalocyanine dyes; oxazine dyes; carbostyryl dyes;napthalenetetracarboxylic acid dyes; porphyrin dyes; bis(styryl)biphenyldyes; acridine dyes; anthraquinone dyes; cyanine dyes; methine dyes;arylmethane dyes; azo dyes; indigoid dyes, thioindigoid dyes, diazoniumdyes; nitro dyes; quinone imine dyes; aminoketone dyes; tetrazoliumdyes; thiazole dyes; perylene dyes, perinone dyes;bis-benzoxazolylthiophene (BBOT); triarylmethane dyes; xanthene dyes;thioxanthene dyes; naphthalimide dyes; lactone dyes; fluorophores suchas anti-stokes shift dyes which absorb in the near infrared wavelengthand emit in the visible wavelength, or the like; luminescent dyes suchas 7-amino-4-methylcoumarin;3-(2′-benzothiazolyl)-7-diethylaminocoumarin;2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole;2,5-bis-(4-biphenylyl)-oxazole; 2,2′-dimethyl-p-quaterphenyl;2,2-dimethyl-p-terphenyl; 3,5,3″″,5″″-tetra-t-butyl-p-quinquephenyl;2,5-diphenylfuran; 2,5-diphenyloxazole; 4,4′-diphenylstilbene;4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran;1,1′-diethyl-2,2′-carbocyanine iodide;3,3′-diethyl-4,4′,5,5′-dibenzothiatricarbocyanine iodide;7-dimethylamino-1-methyl-4-methoxy-8-azaquinolone-2;7-dimethylamino-4-methylquinolone-2;2-(4-(4-dimethylaminophenyl)-1,3-butadienyl)-3-ethylbenzothiazoliumperchlorate; 3-diethylamino-7-diethyliminophenoxazonium perchlorate;2-(1-naphthyl)-5-phenyloxazole; 2,2′-p-phenylen-bis(5-phenyloxazole);rhodamine 700; rhodamine 800; pyrene; chrysene; rubrene; coronene, orthe like, or combinations comprising at least one of the foregoing dyes.Dyes are generally used in amounts of about 1 to about 25 parts byweight, based on 100 parts by weight of the copolycarbonate-polyesterresin.

Where a foam is desired, suitable blowing agents include for example,low boiling halohydrocarbons and those that generate carbon dioxide;blowing agents that are solid at room temperature and when heated totemperatures higher than their decomposition temperature, generate gasessuch as nitrogen, carbon dioxide, or ammonia gas, such asazodicarbonamide, metal salts of azodicarbonamide, 4,4′oxybis(benzenesulfonylhydrazide), sodium bicarbonate, ammoniumcarbonate, or the like, or combinations comprising at least one of theforegoing blowing agents. Blowing agents are generally used in amountsof about 1 to about 50 parts by weight, based on 100 parts by weight ofthe copolycarbonate-polyester resin.

Suitable flame retardant that may be added may be organic compounds thatinclude phosphorus, bromine, and/or chlorine. Non-brominated andnon-chlorinated phosphorus-containing flame retardants may be preferredin certain applications for regulatory reasons, for example organicphosphates and organic compounds containing phosphorus-nitrogen bonds.

One type of exemplary organic phosphate is an aromatic phosphate of theformula (GO)₃P═O, wherein each G is independently an alkyl, cycloalkyl,aryl, alkaryl, or aralkyl group, provided that at least one G is anaromatic group. Two of the G groups may be joined together to provide acyclic group, for example, diphenyl pentaerythritol diphosphate, whichis described by Axelrod in U.S. Pat. No. 4,154,775. Other suitablearomatic phosphates maybe, for example, phenyl bis(dodecyl)phosphate,phenyl bis(neopentyl)phosphate, phenylbis(3,5,5′-trimethylhexyl)phosphate, ethyl diphenyl phosphate,2-ethylhexyl di(p-tolyl)phosphate, bis(2-ethylhexyl)p-tolyl phosphate,tritolyl phosphate, bis(2-ethylhexyl)phenyl phosphate,tri(nonylphenyl)phosphate, bis(dodecyl) p-tolyl phosphate, dibutylphenyl phosphate, 2-chloroethyl diphenyl phosphate, p-tolylbis(2,5,5′-trimethylhexyl)phosphate, 2-ethylhexyl diphenyl phosphate, orthe like. A specific aromatic phosphate is one in which each G isaromatic, for example, triphenyl phosphate, tricresyl phosphate,isopropylated triphenyl phosphate, and the like.

Di- or polyfunctional aromatic phosphorus-containing compounds are alsouseful, for example, compounds of the formulas below:

wherein each G¹ is independently a hydrocarbon having 1 to about 30carbon atoms; each G² is independently a hydrocarbon or hydrocarbonoxyhaving 1 to about 30 carbon atoms; each X is independently a bromine orchlorine; m is 0 to 4, and n is 1 to about 30. Examples of suitable di-or polyfunctional aromatic phosphorus-containing compounds includeresorcinol tetraphenyl diphosphate (RDP), the bis(diphenyl)phosphate ofhydroquinone and the bis(diphenyl)phosphate of bisphenol-A,respectively, their oligomeric and polymeric counterparts, and the like.

Exemplary suitable flame retardant compounds containingphosphorus-nitrogen bonds include phosphonitrilic chloride, phosphorusester amides, phosphoric acid amides, phosphonic acid amides, phosphinicacid amides, tris(aziridinyl) phosphine oxide. When present,phosphorus-containing flame retardants are generally present in amountsof about 1 to about 20 parts by weight, based on 100 parts by weight ofthe copolycarbonate-polyester resin.

Halogenated materials may also be used as flame retardants, for examplehalogenated compounds and resins of formula (13)

wherein R is an alkylene, alkylidene or cycloaliphatic linkage, e.g.,methylene, ethylene, propylene, isopropylene, isopropylidene, butylene,isobutylene, amylene, cyclohexylene, cyclopentylidene, or the like; oran oxygen ether, carbonyl, amine, or a sulfur containing linkage, e.g.,sulfide, sulfoxide, sulfone, or the like. R can also consist of two ormore alkylene or alkylidene linkages connected by such groups asaromatic, amino, ether, carbonyl, sulfide, sulfoxide, sulfone, or thelike.

Ar and Ar′ in formula (13) are each independently mono- orpolycarbocyclic aromatic groups such as phenylene, biphenylene,terphenylene, naphthylene, or the like.

Y is an organic, inorganic, or organometallic radical, for example (1)halogen, e.g., chlorine, bromine, iodine, fluorine or (2) ether groupsof the general formula OE, wherein E is a monovalent hydrocarbon radicalsimilar to X or (3) monovalent hydrocarbon groups of the typerepresented by R or (4) other substituents, e.g., nitro, cyano, and thelike, said substituents being essentially inert provided that there isat least one and preferably two halogen atoms per aryl nucleus.

When present, each X is independently a monovalent hydrocarbon group,for example an alkyl group such as methyl, ethyl, propyl, isopropyl,butyl, decyl, or the like; an aryl groups such as phenyl, naphthyl,biphenyl, xylyl, tolyl, or the like; and aralkyl group such as benzyl,ethylphenyl, or the like; a cycloaliphatic group such as cyclopentyl,cyclohexyl, or the like. The monovalent hydrocarbon group may itselfcontain inert substituents.

Each d is independently 1 to a maximum equivalent to the number ofreplaceable hydrogens substituted on the aromatic rings comprising Ar orAr′. Each e is independently 0 to a maximum equivalent to the number ofreplaceable hydrogens on R. Each a, b, and c is independently a wholenumber, including 0. When b is not 0, neither a nor c may be 0.Otherwise either a or c, but not both, may be 0. Where b is 0, thearomatic groups are joined by a direct carbon-carbon bond.

The hydroxyl and Y substituents on the aromatic groups, Ar and Ar′ canbe varied in the ortho, meta or para positions on the aromatic rings andthe groups can be in any possible geometric relationship with respect toone another.

Included within the scope of the above formula are bisphenols of whichthe following are representative: 2,2-bis-(3,5-dichlorophenyl)-propane;bis-(2-chlorophenyl)-methane; bis(2,6-dibromophenyl)-methane;1,1-bis-(4-iodophenyl)-ethane; 1,2-bis-(2,6-dichlorophenyl)-ethane;1,1-bis-(2-chloro-4-iodophenyl)ethane;1,1-bis-(2-chloro-4-methylphenyl)-ethane;1,1-bis-(3,5-dichlorophenyl)-ethane;2,2-bis-(3-phenyl-4-bromophenyl)-ethane;2,6-bis-(4,6-dichloronaphthyl)-propane;2,2-bis-(2,6-dichlorophenyl)-pentane;2,2-bis-(3,5-dibromophenyl)-hexane; bis-(4-chlorophenyl)-phenyl-methane;bis-(3,5-dichlorophenyl)-cyclohexylmethane;bis-(3-nitro-4-bromophenyl)-methane;bis-(4-hydroxy-2,6-dichloro-3-methoxyphenyl)-methane; and2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane 2,2bis-(3-bromo-4-hydroxyphenyl)-propane. Also included within the abovestructural formula are: 1,3-dichlorobenzene, 1,4-dibromobenzene,1,3-dichloro-4-hydroxybenzene, and biphenyls such as2,2′-dichlorobiphenyl, polybrominated 1,4-diphenoxybenzene,2,4′-dibromobiphenyl, and 2,4′-dichlorobiphenyl as well as decabromodiphenyl oxide, and the like.

Also useful are oligomeric and polymeric halogenated aromatic compounds,such as a copolycarbonate of bisphenol A and tetrabromobisphenol A and acarbonate precursor, e.g., phosgene. Metal synergists, e.g., antimonyoxide, may also be used with the flame retardant. When present, halogencontaining flame retardants are generally present in amounts of about 1to about 25 parts by weight, based on 100 parts by weight of thecopolycarbonate-polyester resin.

Alternatively, the composition may be essentially free of chlorine andbromine. Essentially free of chlorine and bromine as used herein refersto materials produced without the intentional addition of chlorine orbromine or chlorine or bromine containing materials. It is understoodhowever that in facilities that process multiple products a certainamount of cross contamination can occur resulting in bromine and/orchlorine levels typically on the parts per million by weight scale. Withthis understanding it can be readily appreciated that essentially freeof bromine and chlorine may be defined as having a bromine and/orchlorine content of less than or equal to about 100 parts per million byweight (ppm), less than or equal to about 75 ppm, or less than or equalto about 50 ppm. When this definition is applied to the fire retardantit is based on the total weight of the fire retardant. When thisdefinition is applied to the thermoplastic composition it is based onthe total weight of copolycarbonate-copolyester, and fire retardant.

Inorganic flame retardants may also be used, for example salts of C₂₋₁₆alkyl sulfonate salts such as potassium perfluorobutane sulfonate (Rimarsalt), potassium perfluoroctane sulfonate, tetraethylammoniumperfluorohexane sulfonate, and potassium diphenylsulfone sulfonate, andthe like; salts formed by reacting for example an alkali metal oralkaline earth metal (for example lithium, sodium, potassium, magnesium,calcium and barium salts) and an inorganic acid complex salt, forexample, an oxo-anion, such as alkali metal and alkaline-earth metalsalts of carbonic acid, such as Na₂CO₃, K₂CO₃, MgCO₃, CaCO₃, and BaCO₃or fluoro-anion complex such as Li₃AlF₆, BaSiF₆, KBF₄, K₃AlF₆, KAlF₄,K₂SiF₆, and/or Na₃AlF₆ or the like. When present, inorganic flameretardant salts are generally present in amounts of about 1 to about 20parts by weight, based on 100 parts by weight of thecopolycarbonate-polyester resin.

Another useful type of flame retardant is a polysiloxane-polycarbonatecopolymer having polydiorganosiloxane blocks comprise repeatingstructural units of formula (14)

wherein each occurrence of R¹¹ is same or different, and is a C₁₋₁₃monovalent organic radical. For example, R¹¹ maybe a C₁-C₁₃ alkyl group,C₁-C₁₃ alkoxy group, C₂-C₁₃ alkenyl group, C₂-C₁₃ alkenyloxy group,C₃-C₆ cycloalkyl group, C₃-C₆ cycloalkoxy group, C₆-C₁₀ aryl group,C₆-C₁₀ aryloxy group, C₇-C₁₃ aralkyl group, C₇-C₁₃ aralkoxy group,C₇-C₁₃ alkaryl group, or C₇-C₁₃ alkaryloxy group. Combinations of theforegoing R¹¹ groups may be used in the same copolymer. R¹² in formula(6) is a divalent C₁-C₈ aliphatic group. Each M in formula (7) may bethe same or different, and may be a halogen, cyano, nitro, C₁-C₈alkylthio, C₁-C₈ alkyl, C₁-C₈ alkoxy, C₂-C₈ alkenyl, C₂-C₈ alkenyloxygroup, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkoxy, C₆-C₁₀ aryl, C₆-C₁₀ aryloxy,C₇-C₁₂ aralkyl, C₇-C₁₂ aralkoxy, C₇-C₁₂ alkaryl, or C₇-C₁₂ alkaryloxy,wherein each n is independently 0, 1, 2, 3, or 4.

E in formula (14) is selected so as to provide an effective level offlame retardance to the thermoplastic composition. The value of E willtherefore vary depending on the type and relative amount of eachcomponent in the thermoplastic composition, including the type andamount of polycarbonate, impact modifier, polysiloxane-polycarbonatecopolymer, and other flame retardants. Suitable values for E may bedetermined by one of ordinary skill in the art without undueexperimentation using the guidelines taught herein. Generally, E has anaverage value of 2 to about 1000, specifically about 10 to about 100,more specifically about 25 to about 75. In one embodiment, E has anaverage value of about 40 to about 60, and in still another embodiment,E has an average value of about 50. Where E is of a lower value, e.g.,less than about 40, it may be necessary to use a relatively largeramount of the polysiloxane-polycarbonate copolymer. Conversely, where Eis of a higher value, e.g., greater than about 40, it may be necessaryto use a relatively smaller amount of the polysiloxane-polycarbonatecopolymer.

In one embodiment, M is independently bromo or chloro, a C₁-C₃ alkylgroup such as methyl, ethyl, or propyl, a C₁-C₃ alkoxy group such asmethoxy, ethoxy, or propoxy, or a C₆-C₇ aryl group such as phenyl,chlorophenyl, or tolyl; R² is a dimethylene, trimethylene ortetramethylene group; and R is a C₁₋₈ alkyl, haloalkyl such astrifluoropropyl, cyanoalkyl, or aryl such as phenyl, chlorophenyl ortolyl. In another embodiment, R is methyl, or a mixture of methyl andtrifluoropropyl, or a mixture of methyl and phenyl. In still anotherembodiment, M is methoxy, n is one, R² is a divalent C₁-C₃ aliphaticgroup, and R is methyl.

The polysiloxane-polycarbonate copolymer may be manufactured by reactionof the corresponding dihydroxy polysiloxane with a carbonate source anda dihydroxy aromatic compound of formula (3), optionally in the presenceof a phase transfer catalyst as described above. Suitable conditions aresimilar to those useful in forming polycarbonates. Alternatively, thepolysiloxane-polycarbonate copolymers may be prepared by co-reacting ina molten state, the dihydroxy monomers and a diaryl carbonate ester,such as diphenyl carbonate, in the presence of a transesterificationcatalyst as described above. Generally, the amount of dihydroxypolydiorganosiloxane is selected so as to produce a copolymer comprisingabout 1 to about 60 mole percent of polydiorganosiloxane blocks relativeto the moles of polycarbonate blocks, and more generally, about 3 toabout 50 mole percent of polydiorganosiloxane blocks relative to themoles of polycarbonate blocks. When present, the copolymers may be usedin amounts of about 5 to about 50 parts by weight, more specificallyabout 10 to about 40 parts by weight, based on 100 parts by weight ofthe copolycarbonate-polyester resin.

Anti-drip agents may also be used in the tie layer composition, forexample a fibril forming or non-fibril forming fluoropolymer such aspolytetrafluoroethylene (PTFE). The anti-drip agent may be encapsulatedby a rigid copolymer as described above, for examplestyrene-acrylonitrile copolymer (SAN). PTFE encapsulated in SAN is knownas TSAN. Encapsulated fluoropolymers may be made by polymerizing theencapsulating polymer in the presence of the fluoropolymer, for examplean aqueous dispersion. TSAN may provide significant advantages overPTFE, in that TSAN may be more readily dispersed in the composition. Asuitable TSAN may comprise, for example, about 50 wt. % PTFE and about50 wt. % SAN, based on the total weight of the encapsulatedfluoropolymer. The SAN may comprise, for example, about 75 wt. % styreneand about 25 wt. % acrylonitrile based on the total weight of thecopolymer. Alternatively, the fluoropolymer may be pre-blended in somemanner with a second polymer, such as for, example, an aromaticpolycarbonate resin or SAN to form an agglomerated material for use asan anti-drip agent. Either method may be used to produce an encapsulatedfluoropolymer. Antidrip agents are generally used in amounts of 0.1 to 5percent by weight, based on 100 parts by weight of thecopolycarbonate-polyester resin.

Radiation stabilizers may also be present, specifically gamma-radiationstabilizers. Suitable gamma-radiation stabilizers include alkylenepolyols such as ethylene glycol, propylene glycol, 1,3-propanediol,1,2-butanediol, 1,4-butanediol, meso-2,3-butanediol, 1,2-pentanediol,2,3-pentanediol, 1,4-pentanediol, 1,4-hexandiol, and the like;cycloalkylene polyols such as 1,2-cyclopentanediol, 1,2-cyclohexanediol,and the like; branched alkylenepolyols such as2,3-dimethyl-2,3-butanediol (pinacol), and the like, as well asalkoxy-substituted cyclic or acyclic alkanes. Unsaturated alkenols arealso useful, examples of which include 4-methyl-4-penten-2-ol,3-methyl-pentene-3-ol, 2-methyl-4-penten-2-ol,2,4-dimethyl-4-penten-2-ol, and 9-decen-1-ol, as well as tertiaryalcohols that have at least one hydroxy substituted tertiary carbon, forexample 2-methyl-2,4-pentanediol (hexylene glycol), 2-phenyl-2-butanol,3-hydroxy-3-methyl-2-butanone, 2-phenyl-2-butanol, and the like, andcyclic tertiary alcohols such as 1-hydroxy-1-methyl-cyclohexane. Certainhydroxymethyl aromatic compounds that have hydroxy substitution on asaturated carbon attached to an unsaturated carbon in an aromatic ringcan also be used. The hydroxy-substituted saturated carbon may be amethylol group (—CH₂OH) or it may be a member of a more complexhydrocarbon group such as —CR⁴HOH or —CR₂ ⁴OH wherein R⁴ is a complex ora simple hydrocarbon. Specific hydroxy methyl aromatic compounds includebenzhydrol, 1,3-benzenedimethanol, benzyl alcohol, 4-benzyloxy benzylalcohol and benzyl benzyl alcohol. 2-Methyl-2,4-pentanediol,polyethylene glycol, and polypropylene glycol are often used forgamma-radiation stabilization. Gamma-radiation stabilizing compounds aretypically used in amounts of 0.001 to 1 wt %, more specifically 0.01 to0.5 wt %, based on 100 parts by weight of the copolycarbonate-polyesterresin.

Thermoplastic compositions comprising the copolycarbonate-polyesterresin and one or more of the optional other polymer(s), optionalfiller(s), and optional additive(s) foregoing may be manufactured bymethods generally available in the art, for example, in one embodiment,in one manner of proceeding, powdered copolycarbonate-polyester resinand/or other optional components are first blended, in a HENSCHEL-Mixer®high speed mixer. Other low shear processes, including but not limitedto hand mixing, may also accomplish this blending. The blend is then fedinto the throat of a twin-screw extruder via a hopper. Alternatively,one or more of the components may be incorporated into the compositionby feeding directly into the extruder at the throat and/or downstreamthrough a sidestuffer. Such additives may also be compounded into amasterbatch with a desired polymeric resin and fed into the extruder.The extruder is generally operated at a temperature higher than thatnecessary to cause the composition to flow. The extrudate is immediatelyquenched in a water batch and pelletized. The pellets can be one-fourthinch (6.35 mm) long or less as desired. Such pellets may be used forsubsequent molding, shaping, or forming.

Shaped, formed, or molded articles comprising thecopolycarbonate-polyester compositions are also provided. Thecopolycarbonate-polyester compositions may be molded into useful shapedarticles by a variety of means such as injection molding, extrusion,rotational molding, blow molding and thermoforming to form articles suchas, for example, computer and business machine housings such as housingsfor monitors, handheld electronic device housings such as housings forcell phones, electrical connectors, and components of lighting fixtures,ornaments, home appliances, roofs, greenhouses, sun rooms, swimming poolenclosures, and the like. In addition, the polycarbonate compositionsmay be used for such application as automotive bezels and reflectors.

The copolycarbonate-polyester compositions are further illustrated bythe following non-limiting examples, which are based on the followingcomponents.

EXAMPLE 1

To a 75-Liter (L) reactor equipped with mechanical agitation, condenser,and caustic scrubber vent system was charged 1150 gram (g) of BHPD (2.92moles), 1950 g of BPA (8.55 moles), 130 g of p-cumylphenol (0.61 moles),25 milliliters (ml) of a 70 wt % aqueous methyltributylammonium chloridesolution (0.07 moles), 10 g of sodium gluconate, 13 L of deionized (DI)water, and 22 L of methylene chloride. A 50/50 wt % mixture of moltenterephthaloyl dichloride/isophthaloyl dichloride (2100 g, 9.1 mole) wasadded at a rate of 100 g/minute while 50 wt % caustic solution was addedat a rate sufficient to maintain the a reaction at a pH of 9.0. Afterthe diacid chloride addition was complete, the reaction was stirred for10 minutes at pH 9. Phosgene (300 g, 3.03 moles) was then added at arate of 100 g/minute to the reactor while 50 wt % caustic was added tomaintain a pH of 9.0. Triethylamine (15 ml, 0.1 moles) dissolved in 1 Lmethylene chloride was then added and the reaction stirred at pH 9 for 5minutes. An additional 200 g phosgene (2.02 moles) was added at a rateof 100 g/minute while sufficient 50 wt % caustic was added to maintainthe pH at 9.0. The reactor was then purged with nitrogen gas for 10minutes to remove any residual phosgene.

The reactor contents were then transferred to another tank andcentrifuged to remove the aqueous (brine) layer. The organic layer(containing copolymer) was washed with aqueous acid and then withdeionized water until residual chloride ion levels were less than 2parts per million (ppm). The copolymer was isolated by steamprecipitation, followed by drying under N₂.

The dried resin powder had weight average molecular weight (Mw) of 28808and a polydispersity index of 2.20 as determined by gel permeationchromatography (GPC) using a polycarbonate standard. The copolymer wasfound to have less than 1 ppm triethylamine, 0.63 ppm chloride ion, 0.03ppm Fe, 73 ppm residual BPA, and 37 ppm residual BHPD. Differentialscanning calorimetry (DSC) showed the copolymer to have a Tg of 219° C.Melt volume rate (MVR) was determined at 330° C. using a 2.16-kilogramweight, over 6 minutes, in accordance with ASTM D1238-04, and found toequal 1.8.

EXAMPLE 2

To a 75-L reactor equipped with mechanical agitation, condenser, andcaustic scrubber vent system was charged 1200 g of BHPD (3.05 moles), 25g p-cumylphenol (0.21 moles), 25 ml of a 70 wt % aqueousmethyltributylammonium chloride solution (0.07 moles), 10 g sodiumgluconate, 9 L DI water, and 14 L methylene chloride. A 50 wt % causticsolution (500 g of solution, 6.25 moles NaOH) was added as the reactionmixture was stirred. A 50/50 (by weight) mixture of molten terephthaloyldichloride/isophthaloyl dichloride (508 g, 2.2 mole) was added at a rateof 50 g/minute while sufficient 50 wt % caustic was added to maintain areaction pH of greater than 8.5. After the diacid chloride addition wascomplete, the reaction was stirred for 10 minutes at a pH of 9. BPA(1150 g, 5.04 moles), p-cumylphenol (75 g, 0.35 moles), triethylamine(30 ml, 0.2 moles), DI water (6 L), and methylene chloride (7 L) werethen added to the reactor. Phosgene (750 g, 7.57 moles) was then addedat a rate of 80 g/minute to the reactor while 50 wt % caustic was addedto maintain a pH of 9.0. An additional 100 g phosgene (1.01 moles) wasadded at a rate of 80 g/minute while sufficient 50 wt % caustic wasadded to maintain a pH of 9.0. The reactor was then purged with nitrogengas for 10 minutes to remove any residual phosgene.

The reactor contents were then transferred to another tank andcentrifuged to remove the aqueous layer. The organic layer (containingcopolymer) was washed with aqueous acid and then with deionized wateruntil residual chloride ion levels were less than 2 ppm. The copolymerwas isolated by steam precipitation followed by drying under nitrogen.

The dried resin powder had a weight average molecular weight of 28276and a PDI of 2.57, determined as above. The copolymer was further foundto have less than 1 ppm triethylamine, 0.77 ppm chloride ion, 0.03 ppmFe, 72 ppm residual BPA, and 25 ppm residual BHPD. DSC of this polymershowed a Tg of 205° C. MVR (330° C./2.16 kg/6 minutes)=4.0.

EXAMPLES 3-5 AND COMPARATIVE EXAMPLES A-B

The properties of three copolycarbonate-polyesters produced as describedabove (Examples 3-5) were compared to two copolycarbonates having unitsderived from BPA and BHPD (Examples A-B). Production of suchcopolycarbonates is described, for example, in U.S. Pat. Nos. 5,344,910and 5,455,310. The comparison is set forth in the Table below.

“Time dwell” refers to a rheological test requiring holding a sample ata specified temperature for a specified time, and monitoring the changein viscosity. More stable resins will undergo smaller changes inviscosity.

Weight loss was determined via TGA after holding the samples at theindicated temperature for 30 minutes. TABLE 1 Test Ex. 3 Ex. 4 Ex. 5 A BTg (DSC) 212.8 223.9 218.8 220.2 220 MVR (330° C., 2.15 kg) 1.81 1.381.8 5 3 Viscosity at 350° C. 1084.5 1304.3 1432.1 456.4 560 Viscosity at380° C. 589.1 592.9 671.4 148.4 Time dwell at 350° C. −17 −17 −13 −30Time dwell at 380° C. −41 −43 −37 Weight Loss at 350° C. 1.24 0.96 0.861.17 Weight Loss at 380° C. 2.09 3.1 2.51 4

As may be seen by reference to Table 1, the Tg of thecopolycarbonate-polyesters is comparable to that of the high heatpolycarbonates.

Further, the time dwell at 350° C. suggest thecopolycarbonate-polyesters are more thermally stable than thecorresponding polycarbonates. The materials of this invention showed a13-17% viscosity drop when held at 350° C. for 30 minutes, whereas thecomparable polycarbonate showed a 30% viscosity drop. Although at 380°C. the copolycarbonate-polyesters lose viscosity (37-43%), thecomparative polycarbonate lost so much viscosity that reliable numberscould not be obtained.

The comparative samples held at 380° C. showed a weight loss of 4%,while the copolycarbonate-polyesters lost only 2.1-3.1 wt %, suggestingthat the polyestercarbonates are more thermally stable.

EXAMPLE 6 AND COMPARATIVE EXAMPLES C-D

The hydrolytic stability of a copolycarbonate-polyester produced asdescribed above (Example 6) was compared to three copolycarbonateshaving units derived from BPA and BHPD (Examples C-D) having anequivalent Tg. Production of such polycarbonates is described, forexample, in U.S. Pat. Nos. 5,344,910 and 5,455,310. Homogeneoushydrolysis was carried out in an anisole/methyl ethyl ketone (MEK)/watermixture at 60° C. A 2.00 gram sample of polymer was weighed into a 4 ozvial and dissolved in 50 mL of a 3:2 (by volume) mixture ofanisole/methyl ethyl ketone at room temperature. Distilled water (0.15ml, 3400 ppm) was added to the sample and the vial was sealed and placedin an oven at 60° C. Aliquots (about 8 ml) were periodically removedfrom the sample and the resin was precipitated into 150 ml stirringmethanol at ambient temperature. The solid polymer was isolated viafiltration, washed with methanol, and dried under vacuum at roomtemperature. Molecular weight for each sample was determined via GPC.Results are shown in Table 2. TABLE 2 Hydrolysis Sample, MolecularWeight time (hours) C D E Example 6 20 24265 25139 24896 26991 44 2083522237 21803 26022 102 16383 17240 17547 25286

The above data shows that the copolyester-copolycarbonates maintainmolecular weight significantly better than prior art copolycarbonateshaving under hydrolytic conditions. This indicates that incorporatingthe high heat monomer into polyester blocks improves the hydrolyticstability of the polymers.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise. The endpoints of all rangesreciting the same property or quantity are independently combinable andinclusive of the recited endpoint. All references are incorporatedherein by reference. “Optional” or “optionally” means that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances where the event occurs andinstances where it does not. Compounds are described using standardnomenclature. For example, any position not substituted by any indicatedgroup is understood to have its valency filled by a bond as indicated,or a hydrogen atom. A dash (“-”) that is not between two letters orsymbols is used to indicate a point of attachment for a substituent. Forexample, —CHO is attached through carbon of the carbonyl group.

While typical embodiments have been set forth for the purpose ofillustration, the foregoing descriptions should not be deemed to be alimitation on the scope herein. Accordingly, various modifications,adaptations, and alternatives may occur to one skilled in the artwithout departing from the spirit and scope herein.

1. A copolycarbonate-polyester, comprising units of formula

wherein at least 60 percent of the total number of R¹ groups aredivalent aromatic organic radicals and the balance thereof are divalentaliphatic or alicyclic radicals; units of formula

wherein T is a C₇₋₂₀ divalent alkyl aromatic radical or a C₆₋₂₀ divalentaromatic radical, and D is a divalent C₆₋₂₀ aromatic radical; and unitsof the formula

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl or phenyl group, each c is independently 0 to 4,and T is as described above.
 2. The copolycarbonate-polyester of claim1, wherein at least a portion of the R¹ groups are derived from adihydroxy compound of the formula

wherein R^(a) and R^(b) are each independently a halogen atom or amonovalent C₁₋₆ alkyl group; p and q are each independently integers of0 to 4; and X^(a) is one of the following groups:

wherein R^(c) and R^(d) are each independently a hydrogen atom or aC₁₋₂₉ alkyl group, or R^(c), C, and R^(d) taken together are a divalentC₃₋₁₀ cycloalkyl group that is optionally substituted with one or moreC₁₋₁₀ alkyl groups, and R^(e) is a divalent hydrocarbon group.
 3. Thecopolycarbonate-polyester of claim 2, wherein p and q are each zero andX^(a) is 2,2-propylene.
 4. The copolycarbonate-polyester of claim 1,wherein T is a C₆₋₂₀ divalent aromatic radical.
 5. Thecopolycarbonate-polyester of claim 1, wherein T is a divalentisophthaloyl radical and/or a divalent terephthaloyl radical.
 6. Thecopolycarbonate-polyester of claim 1, wherein D is derived from anaromatic diol of the formula

wherein R^(a) and R^(b) are each independently a halogen atom or amonovalent C₁₋₆ alkyl group; p and q are each independently integers of0 to 4; and X^(a) is one of the following groups:

wherein R^(c) and R^(d) are each independently a hydrogen atom or aC₁₋₂₉ alkyl group, or R^(c), C, and R^(d) taken together are a divalentC₃₋₁₀ cycloalkyl group that is optionally substituted with one or moreC₁₋₁₀ alkyl groups, and R^(e) is a divalent hydrocarbon group.
 7. Thecopolycarbonate-polyester of claim 6, wherein p and q are each zero andX^(a) is 2,2-propylene.
 8. The copolycarbonate-polyester of claim 1,wherein each c is
 0. 9. The copolycarbonate-polyester of claim 1,wherein each c is 0 and R⁴ is a phenyl group.
 10. Thecopolycarbonate-polyester of claim 1, wherein the number of R¹ groupsthat are derived from a monomer of the formula

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl or phenyl group, and each c is independently 0 to4, is less than 50% of the total number of R¹ groups, as determined byproton NMR.
 11. The copolycarbonate-polyester of claim 1, having a Tg of180° C. to 300° C.
 12. An article comprising thecopolycarbonate-polyester of claim
 1. 13. A method of preparing acopolycarbonate-polyester, comprising reacting a reactive polyesterintermediate comprising units of formula

wherein T is a C₇₋₂₀ divalent alkyl aromatic radical or a C₆₋₂₀ divalentaromatic radical, and D is a divalent C₆₋₂₀ aromatic radical; and unitsof formula

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl, or phenyl group, each c is independently 0 to 4,with a carbonate source and a compound of the formula HO—R¹—OH in areaction mixture comprising water, a substantially water-immiscibleorganic solvent, and a base, to provide a copolycarbonate-polyester. 14.The method of claim 13, wherein D and at least a portion of the R¹derived from a dihydroxy compound of the formula

wherein R^(a) and R^(b) are each independently a halogen atom or amonovalent C₁₋₆ alkyl group; p and q are each independently integers of0 to 4; and X^(a) is one of the following groups:

wherein R^(c) and R^(d) are each independently a hydrogen atom or aC₁₋₂₉ alkyl group, or R^(c), C, and R^(d) taken together are a divalentC₃₋₁₀ cycloalkyl group that is optionally substituted with one or moreC₁₋₁₀ alkyl groups, and R^(e) is a divalent hydrocarbon group.
 15. Themethod of claim 13, wherein p and q are each zero and X^(a) is2,2-propylene.
 16. The method of claim 13, wherein each c is
 0. 17. Themethod of claim 13, wherein each c is 0 and R⁴ is a phenyl group. 18.The method of claim 13, wherein the number of R¹ groups that are derivedfrom a monomer of the formula

wherein R² and R³ are each independently a halogen or a C₁₋₆ alkylgroup, R⁴ is a methyl or phenyl group, and each c is independently 0 to4, is less than 50% of the total number of R¹ groups, as determined byproton NMR.
 19. A copolycarbonate-polyester manufactured by the methodof claim
 13. 20. An article comprising copolycarbonate-polyestermanufactured by the method of claim 13.